Fix valgrind issue
Fix valgrind issue

==27188== Mismatched free() / delete / delete []
==27188==    at 0x4C2E80F: operator new[](unsigned long) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==27188==    by 0x418840: primesieve::SieveOfEratosthenes::allocate() (in /home/kim/Desktop/primesieve-master/build/primesieve)
kimwalisch/primesieve,kimwalisch/primesieve,kimwalisch/primesieve